For what it's worth I did the whole IR rather than the bridge a couple of years ago. I used the ASA guides (one for written, one for oral), plus Rod Machado's superb online learning material. The ASA written test guide includes subscription for a load of online practice tests, which were excellent.
I sailed through the written using those, and Rod Machado's material was superb for understanding all things IFR in the USA. The oral was the real challenge, and I confess I took two goes, but the ASA oral test guide + Rod Machado did get me through second time.
I would recommend the same for anybody doing any flavour of US IR now, but with SPECIAL attention (i.e. memorise the whole damned thing) to the oral exam guide.
G